深圳地区饮用水中三氯乙醛生成特性与控制方法研究

发布时间：2019-02-17 14:25

【摘要】：消毒副产物（DBPs）问题是全球关注的水质安全问题。我国2006年颁布的饮用水水质标准首次将三氯乙醛（CH）列入其中，但目前国内甚少开展相关研究，对于其影响因素没有明确的结论，缺少全面的针对性控制指导方法。而深圳的水源水质特征、水处理工艺、以及区域、气候条件等特点，往往易存在较大的CH超标风险。常规控制DBPs方式缺乏针对性，很难达到水厂生产中要求的经济高效的目标。因此，本文旨在针对深圳地区水源水质特点，水处理工艺条件的基础上，开展对饮用水中CH生成特性与控制技术的研究，为预防及处理深圳市给水厂CH超标状况提供技术指导。 本文以深圳水库原水为重点研究对象，探讨加氯量、pH值、水温等因素对CH生成的影响，为形成控制方案提供指导。研究强化混凝、粉末活性炭、改变消毒剂的投加方式和类型、活性炭滤池等方法对CH的控制效果。得到主要成果如下： （1）实验室模拟氯化条件下氯投加量、反应时间、pH值、水温对CH生成的影响为：CH的生成量随投氯量的增加而增大，不同水源不同季节平衡浓度不同；pH值7.5时，CH的生成量最高；随反应时间延长CH生成量增大，24h浓度达到最大值；反应温度小于20℃时CH生成量随温度改变不大，，温度高于30℃生成量显著增加；CH同三卤甲烷（THMs）生成量线性相关，皮尔逊系数为0.878。 （2）以现有水厂工艺为依托，筛选出切实可行的控制方法，以实验室小试的条件下研究调整加氯方式、氯胺消毒、高锰酸钾替代前加氯、粉末活性炭吸附CH前体物、强化混凝5种方法对CH的控制效果，得出：前加氯量是控制出厂水中CH含量的重要因素；前加0.5mg/L高锰酸钾工艺出厂水CH含量比前加氯0.8mg/L工艺的低43.7%；50mg/L的粉末活性炭浓度为吸附CH前体物的近饱和量，20~30min的接触时间能够保证CH前体物有效去除；当聚合氯化铝（PAC）投加量增加到4mg/L时，前体物去除率最大，为65.3%；PAC投加量为2mg/L时，pH值为7时CH前体物去除率达到最大值57.6％，投加助凝剂聚丙烯酰胺（PAM）有助于混凝去除CH前体物。 （3）以实验室小试的控制结论为指导，在南山水厂进行生产性实验，对水厂原工艺各阶段CH及其前体物进行调查并通过改变工艺研究各方法对CH的控制情况，得出：CH随工艺流程的推进而增加，混凝沉淀是去除前体物的关键步骤，去除率为22.5%。CH生成率（出厂水CH生成量比原水CH生成势）从低到高的顺序为：粉炭、前加氯0mg/L、粉炭+高锰酸钾、高锰酸钾、原工艺（前加氯0.3mg/L）、前加氯0.6mg/L，数值为：5.4%、6.7%、8.4%、14.0%、27.6%、62.2%。 （4）在沙头角水厂进行生产性实验，研究活性炭滤池对CH及其前体物的去除效果，得出：活性炭滤池能有效去除水中已生成的CH，平均去除率为37.6%，而含氯水经过砂滤池后CH浓度明显升高。活性炭滤池对CH前体物的平均去除率为25.3%，明显高于砂滤池的9.6%，且去除效果稳定。
[Abstract]:Disinfection by-product (DBPs) is a global concern about water quality safety. Trichloroacetaldehyde (CH) was first listed in the drinking water quality standard issued in China in 2006, but at present, there are few related studies in our country, there is no clear conclusion on its influencing factors, and there is no comprehensive targeted control guidance method. However, the characteristics of water quality, water treatment process, regional and climatic conditions in Shenzhen are apt to lead to higher risk of CH exceeding the standard. Due to the lack of pertinence in conventional DBPs control, it is difficult to achieve the economic and efficient target required in water plant production. Therefore, the purpose of this paper is to study the characteristics and control technology of CH in drinking water based on the characteristics of water quality and the technological conditions of water treatment in Shenzhen area, so as to provide technical guidance for the prevention and treatment of CH exceeding the standard in Shenzhen water supply plant. This paper focuses on the study of raw water of Shenzhen Reservoir, discusses the influence of chlorine addition, pH value and water temperature on the formation of CH, and provides guidance for the formation of control scheme. The control effect of enhanced coagulation, powdered activated carbon, changing the dosage and type of disinfectant and activated carbon filter on CH was studied. The main results are as follows: (1) the effects of chlorine dosage, reaction time, pH value and water temperature on the formation of CH under simulated chlorination in laboratory are as follows: the amount of CH is increased with the increase of chlorine dosage. The equilibrium concentrations of different water sources are different in different seasons. When the pH value was 7.5, the yield of CH was the highest, the amount of CH increased with the increase of reaction time, and the concentration of CH reached the maximum at 24 h. When the reaction temperature was less than 20 鈩

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